How can I setup the verification and approval process of Invoicing to follow the PO Policy of the Supplier Card as below if the default policy for verification is PO Policy and we have set the vendor card up to not require a PO why does it require we put a PO in at the approval stage? If we choose Non-PO Policy then even if the Supplier Card does require a PO it does not during the approval process require one to be entered?
If the invoice is created under your PO Policy, the system will always require a PO# to associate/match the invoice to. If the invoice truly does not require a PO, you'll need to create the invoice under your non-PO policy in order for the system to allow submission without a PO#.
If you need a rule to trigger specific vendors to require a PO, you can do that using a custom field and audit rule. For further assistance, you can submit a case with Support.